Identifying route to stall flutter through stochastic bifurcation analysis

Rajagopal V Bethi,J Venkatramani,Sai Vishal Reddy Gali,N Maia,Z Dimitrovová

doi:10.1051/matecconf/201821102011

Rajagopal V Bethi, J Venkatramani + Show 3 more

Open Access

https://doi.org/10.1051/matecconf/201821102011

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Journal: MATEC Web of Conferences	Publication Date: Jan 1, 2018
License type: CC BY 4.0

Affiliation: Shiv Nadar University

Abstract

The interaction of an elastic structure such as an airfoil and fluid flow can give rise to nonlinear phenomenon such as limit cycle oscillations, period doubling or chaos. These phenomena are indicated by a change in the stability behaviour of the dynamical known as bifurcations. Presence of viscous effects in the fluid flow can give rise to flow separation which causes a stability change in the system that is identified to happen via a Hopf bifurcation. In such cases, the airfoil exhibits limit cycle oscillations which are torsionally dominant, known as stall flutter. Despite identifying the route to stall flutter under uniform flow conditions, investigating a stall problem under stochastic wind has received minimal attention. The ability of fluctuating flows to change the stability boundaries and disrupt the route to flutter, compels the need to carry out a stochastic analysis of stalling airfoils. Study of stall flutter in such systems under the influence of a time varying sinusoidal gust is undertaken and the route to flutter is identified by carrying out a stochastic bifurcation analysis.

Highlights

Aeroelasticity is the study of interaction of aerodynamic and elastic forces that arise when an elastic structure such as airfoil is subjected to a fluid flow [1,2]
The interaction of these forces can give rise to complex nonlinear phenomenon such as stall, limit cycle oscillations or chaos [2,3] and are indicated by a change in the qualitative features in the dynamical system known as bifurcations
Bifurcation is a change in the stability behaviour of a nonlinear dynamical system that could result in qualitatively different dynamical responses, leading to topological changes in the phase space, as one or more parameter(s) which the system is dependent on is/are varied [4,5]

Summary

Introduction

Aeroelasticity is the study of interaction of aerodynamic and elastic forces that arise when an elastic structure such as airfoil is subjected to a fluid flow [1,2]. The interaction of these forces can give rise to complex nonlinear phenomenon such as stall, limit cycle oscillations or chaos [2,3] and are indicated by a change in the qualitative features in the dynamical system known as bifurcations.

Results

Conclusion